Multistage low-temperature refrigeration machine

Abstract

The invention relates to a multistage low-temperature refrigeration machine with a first stage in the form of a displacer refrigerator ( 1 ) as well as at least one further stage in the form of a pulse tube refrigerator ( 25 ); in order to suppress vibrations it is proposed that a flexible component ( 45 ) designed to prevent the spread of vibrations be placed between the displacer refrigerator ( 1 ) and the pulse tube refrigerator ( 25 ).

What is claimed is:  
     
       1. A multistage low-temperature refrigeration machine comprising a first stage in the form of a displacer refrigerator; at least one additional stage in the form of a pulse tube refrigerator; and a flexible component located between the displacer refrigerator and the pulse tube refrigerator, for preventing the spread of vibrators between said stages wherein the flexible component is part of a gas supply line for the pulse tube refrigerator and in which a working gas is supplied to the pulse tube refrigerator via said gas supply line, said gas supply line being linked to a cycle of the working gas for the displacer refrigerator. 
     
     
       2. A machine according to claim  1 , wherein the flexible component is a metallic section of corrugated hose. 
     
     
       3. A machine according to claim  1 , wherein the flexible component is a section consisting of plastic hose. 
     
     
       4. A machine according to claim  1 , wherein the gas supply line is connected via a pair of separate lines to the high pressure side and low pressure sides, respectively, of a compressor, said compressor being contained in the cycle for the working gas. 
     
     
       5. A machine according to claim  1 , including a regenerative heat exchanger disposed between the pulse tube refrigerator and the cycle of the working gas for the displacer refrigerator. 
     
     
       6. A machine according to claim  1  including a heat exchanger disposed along said gas supply line, said heat exchanger being coupled thermally to a cold end of the displacer refrigerator. 
     
     
       7. A machine according to claim  6 , including a thermal link for linking the cold end of the displacer, said thermal link being flexible. 
     
     
       8. A machine according to claim  1 , wherein said pulse tube refrigerator includes a pulse tube, said machine including a regenerator disposed within said gas supply line in which a warm end of said pulse tube and an end of the regenerator facing away from the pulse tube are thermally linked to each other. 
     
     
       9. A cryostat used in conjunction with a multistage low-temperature refrigeration machine, said cryostat having a housing for retaining an object to be cooled, said machine comprising a first stage in the form of a displacer refrigerator, at least one additional stage in the form of a pulse tube refrigerator, and a flexible component located between the displacer refrigerator and the pulse tube refrigerator for preventing the spread of vibrations between said stages, said cryostat including a shielding stage thermally coupled to at least one of a cold end of the displacer refrigerator and a warm end of the pulse tube refrigerator, and in which the object to be cooled is thermally coupled to a cold end of the pulse tube refrigerator wherein the object to be cooled is a tank filled with liquid helium, and in which the cold end of the pulse tube refrigerator is thermally coupled to a helium re-filling port of the tank. 
     
     
       10. A multistage low-temperature refrigeration machine comprising a first stage in the form of a displacer refrigerator; at least one additional stage in the form of a pulse tube refrigerator; and a flexible component located between the displacer refrigerator and the pulse tube refrigerator, for preventing the spread of vibrators between said stages, and in which the flexible component is part of a gas supply line for the pulse tube refrigerator, wherein the gas supply line is connected to a cold end of a working area defined within said displacer refrigerator. 
     
     
       11. A cryostat used in conjunction with a multistage low-temperature refrigeration machine, said cryostat having a housing for retaining an object to be cooled, said machine comprising a first stage in the form of a displacer refrigerator, at least one additional stage in the form of a pulse tube refrigerator, and a flexible component located between the displacer refrigerator and the pulse tube refrigerator for preventing the spread of vibrations between said stages, said cryostat including a shielding stage thermally coupled to at least one of a cold end of the displacer refrigerator and a warm end of the pulse tube refrigerator, and in which the object to be cooled is thermally coupled to a cold end of the pulse tube refrigerator, wherein said shielding stage includes a thermal link portion for linking with the warm end of the pulse tube refrigerator, and a second flexible component for preventing the spread of vibrations, said second flexible component being provided between the thermal link portion and the remainder of the shielding stage. 
     
     
       12. A cryostat according to claim  11 , wherein said second flexible component consists of a plurality of upper strips. 
     
     
       13. A cryostat used in conjunction with a multistage low-temperature refrigeration machine, said cryostat having a housing for retaining an object to be cooled, said machine comprising a first stage in the form of a displacer refrigerator, at least one additional stage in the form of a pulse tube refrigerator, and a flexible component located between the displacer refrigerator and the pulse tube refrigerator for preventing the spread of vibrations between said stages, said cryostat including a shielding stage thermally coupled to at least one of a cold end of the displacer refrigerator and a warm end of the pulse tube refrigerator, and in which the object to be cooled is thermally coupled to a cold end of the pulse tube refrigerator wherein, the object to be cooled is a magnet made of a superconducting material wherein the warm end of the pulse tube thermometer is coupled to the shielding stage in addition to the cold end of the displacer refrigerator.